| (19) |
 |
|
(11) |
EP 0 392 674 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
|
09.10.1991 Bulletin 1991/41 |
| (43) |
Date of publication A2: |
|
17.10.1990 Bulletin 1990/42 |
| (22) |
Date of filing: 16.03.1990 |
|
| (51) |
International Patent Classification (IPC)5: B29C 51/10
// B29K79:00 |
|
| (84) |
Designated Contracting States: |
|
DE FR GB |
| (30) |
Priority: |
13.04.1989 GB 8908340
|
| (71) |
Applicant: BRITISH AEROSPACE PUBLIC LIMITED COMPANY |
|
Farnborough,
Hants. GU14 6YU (GB) |
|
| (72) |
Inventors: |
|
- Voaden, Philip Anthony,
British Aerospace
P.O. Box 5,
Filton,
Bristol BS1 7QW (GB)
- Morse, Eric Donald,
British Aerospace
P.O. Box 5,
Filton,
Bristol BS1 7QW (GB)
|
| (74) |
Representative: Rooney, Paul Blaise et al |
|
British Aerospace plc,
Corporate Intellectual Property Department,
Park East, PO Box 87, Farnborough Aerospace Centre
Farnborough, Hants GU14 6YU
Farnborough, Hants GU14 6YU (GB) |
|
| |
|
| (54) |
A process for the production of a shaped sheet of polyimide |
(57) A process for the production of a shaped sheet of polyimide, includes the steps of
placing a sheet of polyimide (1) to be shaped on a shaped surface of a die (2), sealing
the sheet edges (7) to the die (2), applying a vacuum between the die surface and
the sheet (1) to draw the sheet (1) into contact with the shaped die surface to impart
the required shape to the sheet, placing the die (2) and sheet (1) in a gas containing
autoclave whilst maintaining said vacuum, sealing the autoclave and raising the temperature
therein to a temperature selected in the range of from about 150° to 250°C depending
upon the sheet thickness, raising the pressure in the autoclave to a pressure selected
in the range of from 5 to 15 bar depending upon the sheet thickness and selected temperature,
maintaining the selected temperature and pressure in the autoclave for a time in the
range of from 3 to 15 minutes, reducing the selected temperature in the autoclave
to a temperature in the range of from 25° to 125°C whilst maintanung the selected
pressure, reducing the pressure in the autoclave to ambient pressure, removing the
shaped sheet (5) and die (2) from the autoclave and removing the shaped sheet (5)
from the die (2).
